[Adger Smith]

Those Holley Regulators are a joke.
Less than a .250 hole with a .090 pin passing through the hole... not near enough area to pass a decent volume of fuel. I would bet the area of the jets in you Q-Jet are more than twice the actual area available in those Holley Regs...Size the line based on N/S volume and Regulator volume.
OH! did you notice those nice big fittings on that blue pump and that little feed hole inside....never measured one, all it took was a look, but 1/4 in might be near the size...